The communication system is a facility that enables communication between two more entities such as user terminal equipment and/or network entities and other nodes associated with the communication system. The communication may comprise, for example, a communication of voice, electronic mail (email), text messages, data, multimedia and so on.
A communication may be provided by a fixed line and/or wireless communication interfaces. A feature of wireless communication system is that they provide mobility for the users thereof. An example of communication systems providing wireless communication is a public land mobile network (PLMN). An example of the fixed line system is a public switched telephone network (PSTN).
The communication system typically operates in accordance with a given standard or specification which sets out what the various elements of a system are permitted to do and how that should be achieved. For example, the standard or specification may define if the user or more precisely user equipment is provided with a circuit switched server or a packet switched server or both. Communication protocols and/or parameters, which should be used for the connection, are also typically defined. For example, the manner in which communication is implemented between the user equipment and the elements of the communication network is typically based on a predefined communication protocol. In other words, a specific set of rules on which the communication can be based needs to be defined to enable the user equipment to communicate via the communication system.
The 3G partnership project (3GPP) is defining a reference architecture for the universal mobile telecommunication system (UMTS) core network which will provide the users of user equipment with access to services. The term “service” used in this document should be understood to broadly cover any services or goods which a user may desire, require or be provided with. The term is to be understood to cover the provision of complementary services. In particular, but not exclusively, the term “service” will be understood to include internet protocol multimedia IM services, conferencing, telephoning, gaming, rich call, presence, e-commerce, messaging and instant messaging.
Reference will be made to the 3GPP technical specification TS24.234 and TS23.234, both documents, which are hereby incorporated by reference. Both of these documents relate to WLAN (wireless local area network) inter working. WLAN inter working is inter working between a proposed 3GPP system and the WLAN family of standards. Examples of WLAN radio network type technology include Bluetooth, the IEEE standards 802.11B, 802.11G, 802.11A and HIPERLan-2. The wireless local area network inter working allows a WLAN UE (user equipment) to connect to a WLAN and from there to either a visited PLMN or the home HPLMN. The PLMNs are 3G communication systems. A WLAN UE is all the user equipment, which can be used to allow a 3GPP subscriber to access the WLAN inter working. This may include, for example a computer. It should be appreciated that the WLAN UE may be capable of WLAN access only or may be capable of WLAN and 3GPP system access.
In the proposed specification, the network selection procedure consists of two parts. The first part is radio selection. This is the first phase of network selection and always takes place before VPLMN (visited PLMN) selection. In this phase the WLAN UE selects an access point AP and associates itself with it. The parameter used for the selection of the access point is the SSID (service set ID). In the second part, the VPLMN is selected. After selecting an access point, that is after completion of the radio selection, the WLAN UE may need to select a PLMN through which to authenticate, if more than one is available behind the chosen WLAN. This is called VPLMN selection in the WLAN inter working.
However, the proposed procedure has a problem. After associating with an access point, the WLAN UE initiates the VPLMN selection process. EAP (extensible authentication protocol) as defined in the IETF Internet Engineering Task Force draft as defined in draft-arkko-pppext-eap-aka (EAP AKA (authentication and key agreement) authentication) and draft-haverinen-pppext-eap-sim (EAP SIM (subscriber Identity module)). Both of these documents are hereby incorporated by reference.
When the WLAN user equipment receives an EAP failure indicating that the procedure has failed, it is not always advised as to the reason of the failure. This is disadvantageous because the WLAN UE could end up associating with each available access point until it finds one which supports WLAN inter working and/or has the capability to route the WLAN user equipment authentication signalling to the home server. At this point, it is possible that the WLAN user equipment is not aware whether the AP supports WLAN IW and therefore is not able route EAP signalling to the home AAA server. It may also be possible that the AP supports WLAN inter working with the routing failing for other reasons, for example there is not a direct roaming relationship with the respective home PLMN. Yet another possible cause of failure could be authentication failure at the home server, even if the AP was able to route the signalling to the HPLM.